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Btrfs: pretend page cache & commit code

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-03-01 18:59:40 -05:00
committed by David Woodhouse
parent 79f95c82dc
commit ed2ff2cba7
5 changed files with 558 additions and 28 deletions
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91
fs/btrfs/disk-io.c
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@@ -11,6 +11,8 @@
#include "disk-io.h"
static int allocated_blocks = 0;
int cache_size = 0;
int cache_max = 10000;
static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{
@@ -21,6 +23,25 @@ static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf)
return 0;
}
static int free_some_buffers(struct ctree_root *root)
{
struct list_head *node, *next;
struct tree_buffer *b;
if (root->cache_size < cache_max)
return 0;
list_for_each_safe(node, next, &root->cache) {
b = list_entry(node, struct tree_buffer, cache);
if (b->count == 1) {
BUG_ON(!list_empty(&b->dirty));
list_del_init(&b->cache);
tree_block_release(root, b);
if (root->cache_size < cache_max)
return 0;
}
}
return 0;
}
struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr)
{
struct tree_buffer *buf;
@@ -30,10 +51,14 @@ struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr)
return buf;
allocated_blocks++;
buf->blocknr = blocknr;
buf->count = 1;
buf->count = 2;
INIT_LIST_HEAD(&buf->dirty);
free_some_buffers(root);
radix_tree_preload(GFP_KERNEL);
ret = radix_tree_insert(&root->cache_radix, blocknr, buf);
radix_tree_preload_end();
list_add_tail(&buf->cache, &root->cache);
root->cache_size++;
if (ret) {
free(buf);
return NULL;
@@ -57,7 +82,6 @@ struct tree_buffer *find_tree_block(struct ctree_root *root, u64 blocknr)
return buf;
}
struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
{
loff_t offset = blocknr * CTREE_BLOCKSIZE;
@@ -82,6 +106,24 @@ struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr)
return buf;
}
int dirty_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{
if (!list_empty(&buf->dirty))
return 0;
list_add_tail(&buf->dirty, &root->trans);
buf->count++;
return 0;
}
int clean_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{
if (!list_empty(&buf->dirty)) {
list_del_init(&buf->dirty);
tree_block_release(root, buf);
}
return 0;
}
int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
{
u64 blocknr = buf->blocknr;
@@ -96,9 +138,37 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
return 0;
}
static int __commit_transaction(struct ctree_root *root)
{
struct tree_buffer *b;
int ret = 0;
int wret;
while(!list_empty(&root->trans)) {
b = list_entry(root->trans.next, struct tree_buffer, dirty);
list_del_init(&b->dirty);
wret = write_tree_block(root, b);
if (wret)
ret = wret;
tree_block_release(root, b);
}
return ret;
}
int commit_transaction(struct ctree_root *root)
{
int ret;
ret = __commit_transaction(root);
if (!ret && root != root->extent_root)
ret = __commit_transaction(root->extent_root);
BUG_ON(ret);
return ret;
}
static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root,
struct ctree_root_info *info, int fp)
{
INIT_LIST_HEAD(&root->trans);
INIT_LIST_HEAD(&root->cache);
root->fp = fp;
root->node = NULL;
root->node = read_tree_block(root, info->tree_root);
@@ -157,8 +227,23 @@ int write_ctree_super(struct ctree_root *root, struct ctree_super_block *s)
return 0;
}
static int drop_cache(struct ctree_root *root)
{
while(!list_empty(&root->cache)) {
struct tree_buffer *b = list_entry(root->cache.next,
struct tree_buffer, cache);
list_del_init(&b->cache);
tree_block_release(root, b);
}
return 0;
}
int close_ctree(struct ctree_root *root)
{
drop_cache(root->extent_root);
drop_cache(root);
BUG_ON(!list_empty(&root->trans));
BUG_ON(!list_empty(&root->extent_root->trans));
close(root->fp);
if (root->node)
tree_block_release(root, root->node);
@@ -182,6 +267,8 @@ void tree_block_release(struct ctree_root *root, struct tree_buffer *buf)
free(buf);
BUG_ON(allocated_blocks == 0);
allocated_blocks--;
BUG_ON(root->cache_size == 0);
root->cache_size--;
}
}